Study Design: The study quantifies the portion of racial–ethnic differences in children's controller use that are attributable to differences in need, enabling and predisposing characteristics.

Principal Findings: Non-Hispanic black and Hispanic children were less likely to use controllers than non-Hispanic white children. Blinder-Oaxaca decomposition results indicated that observable characteristics explain less than 40 percent of the overall differential in controller use between non-Hispanic whites and non-Hispanic blacks. In contrast, observable characteristics explain more than two-thirds (71.3 percent) of the overall non-Hispanic white-Hispanic differential in controller use. For non-Hispanic blacks, a majority of the explained differential in controller use were attributed to enabling characteristics. For Hispanics, a significant portion of the explained differential in controller use was attributed to predisposing characteristics. In addition, a larger portion of the differential in controller use was explained by observable characteristics for publicly insured non-Hispanic black and Hispanic children.

Conclusions: The large observed differences in controller use highlight the continuing challenges of ensuring that all U.S. children have access to quality asthma care.